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alright I've found something!

So I've got the cover off the fly wheel and rotating the flywheel around.

(forgive my ignorance of proper motor terminology please)

When the camshaft gets to the point where the conrod is projected the furthest out of the motor, or piston is at the top of its stroke, there is a clunk. It also feels like a magnet is stopping it rotate.

The magnet thats inside the flywheel is not passing that other magnet thing (about 5 o'clock on the motor casing) at that point, its about a quater turn futher on.

To my mind/fingers, it feels like there is movement where the conrod attaches to the crank, but that doesn't seem to be the case.

I can't track down the noise any futher, and I don't know what I'm looking for.

So I can hang onto the flywheel and rotate it 1/8 of a turn back and forth and the noise occurs. Wtf is that?!?!

More help please!

Edit -can I assume that its not gearbox or clutch related as it does it at idle/not in gear??
 
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magnet in side the magneto let go?

not sure man, we flying blind here, and since we've covered alot of things your gonna have to pretty much locate which side of the engine the noise is coming from and pull things apart till you find it
 
ok so which side is it coming from?

still doesnt explain the spark plug issue either lol..

grab hold of the conrod when its at TDC and see if you can move it up and down in the crank.. like check for slop in the conrod bearing.. it will have sideways movement but its up and down tht it shouldnt
 
I can't tell what side its coming from, the sound just seems to come straight out the 'hole'...

the slop is negligible in the conrod, a bearing was my first thought, but it would appear not. Its like a puzzle. Whats different at that very point?! Everything should be the same for the stroke of the engine, but for some reason something else is happening at that point....

I've got no fukin idea....

ARGH...

Back to it I guess...

*and why would it start when I pull the plug out clean it, and put it back in (possibly a poofteeth too far).. Did the piston shock the conrod and damage something back down in the engine?!?q
 
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well theres no evidence of anything hitting the piston. well not in the photo..

its hard for me to say too much more, your just gonna have to remove sht till you find the cause..

but im hearing ya, it does seem strange.
 
just pulled the clutch side of the case, and found something...

A chunk of metal lurking in the bottom.

And then I found where its missing from

The teeth that are on the back of the clutch pack, whatever they are called, well one of those teeth is 3/4 gone...

And the binding is occuring about 1 tooth away from that area....

So now what?!
 
060620101010.jpg


That be the broken bit - what the next plan??! I take it the starter gears can be replaced as per the video...?!

And that 'should' solve it?

Are the DHZ ones an 'upgrade' so this doesn't happen again?
 
Thats you clutch basket gear.. Thats a new clutch basket. DHZ starter gears won't fix it. This should though:
- HD 5 Plate Clutch Unit Kit, Lifan 140cc 150cc, YX GPX 150cc 160cc 155Z Engines - DHZ Mini Moto


When you kick the bike over the shaft that the kick starter is on spins a cog which in turns spins a gear behind the clutch. This cog goes over a shaft but in the clutch. Thus turning the clutch and that big gear on the back of it (Which is broken). When the clutch spins it spins the gear whitch spins the oil slinger cog which turn the crank.
 
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oh wait you need to replace your clucth basket

and the gear to the right of your cutch basket gear is it broken too?
 
yep replace the clutch basket or whole clutch and the gear on the crank as it will be marked or damaged
dhz should have everything you need, just tell him what engine you have..

glad you found the problem..tho it still doesnt explain the spark plug problem you posted in the original post.
 
Alright, so lets get me a shopping list...

I need a:
gasket kit for a lifan/yx 140
Clutch basket?
That other gear? Whats it called? (basically anything that's come in contact should be viewed as suspect yeah?)

Would it be prudent to include anything else whilst I've got the motor apart? Whats the latest with IRK? Is it a good idea for standard paddock putting and trail riding? Do I need to do the kickstart gears whilst I'm in there because they 'will' break?

How do I get those gears out? IS it all covered in that youtube clip?

I need to get this stuff ordered tomorrow so any help would be awesome so its rocking by the weekend.

Ta,
 
well you need a clutch removal tool and you definately need a clutch basket

another member will be able to confirm your other questions
 
lifan/YX? alloy barrel is a YX, cast iron barrel is a lifan.. also lifan has the oil cooler lines in the clutch cover/cases where as the yx has the cooler lines coming from the cam plate on the head.

and yep you will need a castle nut removal tool and a magneto removal tool if your going to upgrade the ignition..
i would go for a lifan 150 outer rotor kit, and a cnc oil slinger. irk's are out dated now.
i would also replace the rings and hone the cylinder for the simple reason that you can and the bore would need honing anyways..
and i think they call that gear the primary gear, but different names from different places, just explain where its located in the engine.

also check that your cases arent cracked behind the kick start gears..its pretty unusual that this gear has snapped off for no reason.
 
woah slow down, words I don't know...

I've got the tool thats screwed into the flywheel/spinnging thing near the front sprocket, to get that off. Is that any help? Or I need something else like this?
Clutch Basket & Oil Sling Remover - DHZ Mini Moto

So one of these clutch things - HD 5 Plate Clutch Unit Kit, Lifan 140cc 150cc, YX GPX 150cc 160cc 155Z Engines - DHZ Mini Moto to replace my one.

Gasket kit - Engine Gasket Kit, GPX YX 150cc 160cc PitserPro 155Z engines - DHZ Mini Moto

Rings to suit yx 140



Upgrading the ignition - whats that mean for me?

Honing the bore - how do I do that, or is that a 'take it to the man' kinda job (no chance on this timeline/budget...)

And do I need to think about doing the kickstart gears whilst the thing is apart...
 
you need a yx140 gasket kit, the yx150 kit you linked is different.
if you have the magneto tool then thats good but youll need the oil slinger tool that you linked as well

that clutch kit will be fine, but ask if he has the 6 plate model in stock yet with the primary gear to suit your engine. this is a better kit that is spose to have the updated damper rubbers.

honing can be done yourself or by any bike/engine shop. look thru my threads and you'll see one i posted today, it has a small run down on honing..

yes id be inspecting the kick start gears and the case for damage(as i said earlier)

the ignition upgrade to the lifan outer rotor kit is to minimize this problem from happening again.
 
so that tooth that was cracked off, well that was the good bit.

As I got home tonight and was changing tools in the shed, I had a quick look, and it would appear that the gear is cracked all the way through, about 2 teeth away fromthe chipped one...

What would cause that?

About to watch some videos to work out how to get more stuff apart...
 
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